| Abbreviation | Definition |
|---|---|
| ITST | Institute of Transport Science Technology |
| ITST | Institute of Transport Science & Technology |
| IUAB | Internal Unity Advisory Board |
| IUCI | Institute of Ulsan Culture Industry |
| IUCP | Idaho Unified Certification Program |
| IUEA | International Ukrainian Economic Association |
| IUEW | International Union Electrical Workers |
| IUEW | International Union of Electrical Workers |
| IUM | Institute of Ultrasound in Medicine |
| IUPAC | International Union of Pure and Applied Chemistry |
| IUPG | Instituto Universitario de Profesiones Gerenciales |
| IVCA | International Visual Communication Association |
| IWA | Independent Wrestling Association |
| IWA | International Women's Association |
| IWCA | International Window Cleaning Association |
| IWCA | International Wine Clubs Association |
| IWCA | International Women's Coffee Association |
| IWCA | International Writing Centers Association |
| IWFA | International Wholesale Furniture Association |
| IWM | Institute of Waste Management |